I don't know.... People told me the same thing with the violin. No teachers nearby; I had never played a musical instrument, and didn't even know how to read music. People said "You can't do this without a teacher, you should have started this as a child, it's a fretless instrument, it's very difficult", etc., and you know what? I taught myself how to read music, and I taught myself the violin and learned the notes by ear. It took me YEARS, but now I can play both classical pieces and celtic fiddle, and quite well, all without a teacher or lessons. So I have a hard time when someone I "can't" do something on my own.... It's not like I want to be Lama; claiming to be an expert and showing others. I just want to learn more about the practice for enrichment and study. Of course it's much more difficult without a teacher, but I never asked if it was okay if I do this, that's between me and my heart. I was just asking for learning resources. I don't see anything wrong with earnest home study & practice, as long as I'm not out there teaching others or claiming to be an expert based on what I learn from home. And I certainly do intend to travel to occasional retreats, etc.; I just don't have a nearby teacher. I don't even know if this is the tradition for me yet, I am simply trying to learn more about it, the reasons for the rituals, etc.
Incidentally, I recently wrote to Robert Thurman and told him of my isolated situation and my desire to learn more about the Tibetan tradition and he didn't make any attempt to dissuade me. He wrote back with some suggested readings and gave me some very sincere advice, none of which was "don't attempt this". I hold him in high esteem, so while I appreciate and respect the opinions of a couple of you that suggested against this, I don't think there's anything wrong with trying to learn more about this practice on my own, with the assistance of reading, reputable websites and input from others about practice.
Also, to be clear: I'm not asking for references on the rituals, etc so I can arbitrarily mimic them, I'm asking about what the rituals are so I can study WHY they perform them. That's all to understand the principals of the fundamentals to determine IF it's even something I want to pursue as personal practice.
Thanks to all for the book references and home study course links so far!